For medical diagnostic purposes, it can be useful to determine the sleep stages experienced by a person during sleep. Such sleep stage determination has traditionally been performed in a laboratory setting, in which the patient is asked to sleep while undergoing the testing. Under such conditions, the patient may to experience abnormal sleep patterns.
The sleep stage determination in such a laboratory setting is commonly performed by affixing a plurality of electrodes on the patient's scalp at various standard positions according to the 10-20 system of electrode placement. Some electrodes are positioned to sense electroencephalographic (EEG) signals, while other electrodes may be positioned to detect electromyographic (EMG) signals or electrooculographic (EOG) signals. The EEG, EMG and EOG signals may be provided to a processing system, including, for example, a neural network for use in determining the stage of sleep experienced by the person according to the detected signals. The described embodiments attempt to address or ameliorate one or more of the disadvantages or shortcomings associated with existing sleep stage determination methods or systems, or to at least provide a useful alternative thereto.